How to get elements with class "a b" and change it to "a" only?

Question

<div class="a b"></div>

Say, I want to change it to:

<div class="a"></div>

And reversely, how to add class "b" to a div with class "a"?

Answer 1

$('.a.b').removeClass('b');

Answer 2

To remove it:

$(".a.b").removeClass("b");

To add it:

$(".a").addClass("b");

Answer 3

To change "a b" to just "a":

$('.a.b').removeClass('b');

To add class "b" to divs with class "a":

$('.a').addClass('b');

Answer 4

Try this for your first question:

$('div').filter('.a, .b').removeClass('b');

and this for your second question:

$('div.a').addClass('b');